It's a rubber liner. I dug a hole sloped with a shallow end, then laid rock around the edges. It has a small box filter with fountain. The pond is about 6ft by 3 ft and a foot and a half deep in the deep side about 300-500 gallons total, I planted cat-tails on the west side to block afternoon sun and wind. It has goldfish year round in it and they have bred for 5 years in that pond. I put a donut heater in it in the winter so it doesn't freeze over solid.-----Jeff Benfer
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